What does all charming people have something to conceal usually their total dependence on the appereciation of others mean?

"All charming people have something to conceal (usually their total dependence on the appreciation of others)" is a cynical statement that means that people are charming (that is, pleasant and easy to interact with) only because they desire the approval of others.

This is untrue. Some people are charming regardless of who they are dealing with or who might notice. People can see charm as a virtue itself rather than a means to an end. Being rude and boorish doesn't guarantee authenticity and being polite and charming doesn't guarantee deception.